The present invention relates to liquid extraction, and more particularly to a method and apparatus for extracting liquid from a body of liquid.
Many industrial, commercial and agricultural applications require the extraction of water from bodies of water such as streams, rivers, lakes and oceans, for example. However, conventional water extraction devices suffer from a number of disadvantages.
In order to supply sufficient volumes of water for many applications, the diameter of an intake hose or other conduit inserted into the water must be sufficiently large that fish and other macroscopic objects may be sucked into the hose. This may cause blockages of the intake conduit or cause other difficulties for the application at hand. Moreover, conventional water extraction devices of this nature have proven to be highly destructive to fish stocks. Accordingly, the United States has enacted legislation requiring industries and other water users to provide fish-protective devices on water intake inlets, and other jurisdictions are also expected to enact such legislation.
One previous fish-protective water extraction device involves attaching a hose to a life preserver, such that an inlet opening of the hose is located beneath the water level. The inlet opening of the hose is covered with a mesh, to prevent the entry of fish or other objects. However, it has been found that such a mesh typically clogs with debris very quickly, requiring frequent intervention to unclog the mesh.
Other extraction devices involve positioning an inlet near the bottom of a body of water, where fewer fish may be found in some cases. However, this approach results in extraction of a considerable amount of silt and other sediment in the water, which may render the water unsuitable for many purposes. For example, such silt and sediment may unduly pollute water required for irrigation, or may cause increased wear on turbine components in hydroelectric stations due to xe2x80x9csand-blastingxe2x80x9d by the silt.
Accordingly, there is a need for an improved water extraction method that reduces the likelihood of harming fish, without unduly compromising the quality of water.
The present invention addresses the above need by providing a method and apparatus for extracting liquid from a body of liquid. The apparatus includes a conduit terminator operable to terminate a conduit, the conduit terminator having an inlet opening to facilitate conduction of liquid from the body of liquid. The apparatus also has a solid object diverter connected to the conduit terminator, the diverter defining a liquid admitting cavity about the inlet opening to impede solid objects from entering the inlet opening while permitting entry of liquid into the cavity for admission into the inlet opening. The apparatus further includes a positioner operable to position the diverter in a position in the liquid body such that the cavity admits liquid from the body of liquid while the inlet opening admits liquid from the cavity.
Thus, the solid object diverter serves to prevent or impede the entry of fish and other solid objects into the inlet opening of the conduit terminator.
Preferably, the positioner includes floats on opposite sides of the diverter, in which case the apparatus extracts liquid from near the surface of the body of liquid, thereby greatly reducing the amount of silt and other sediment admitted into the inlet opening of the conduit terminator.
The apparatus preferably includes a housing for producing a passageway for directing liquid past the solid object diverter, in which case the diverter may be in the housing and the floats may cooperate with the housing. The housing preferably has a wall defining a cavity opening for admitting liquid into the liquid admitting cavity, and further defines a gas vent for permitting gas flow into and out of the liquid admitting cavity.
The apparatus may further include a turbulence producing mechanism operable to produce a turbulent flow of liquid from the housing. It has been found that fish are attracted to turbulence, and accordingly, the turbulence produced by the mechanism tends to attract fish toward an outlet end of the housing rather than toward an inlet end, thus reducing the likelihood that fish will pass through the housing.
Preferably, the turbulence producing mechanism includes a venturi accelerator in or formed by the housing, which serves to produce a high-speed flow as the liquid exits the venturi accelerator, resulting in turbulence behind the outlet end region of the housing. In this regard, the housing may include spaced apart converging walls for forming the venturi accelerator.
Advantageously, the converging walls may be adjustably spaced apart to permit adjustment of the spacing between the converging walls. The converging walls preferably include first and second resilient channel members rigidly attached to respective opposite sides of the housing at an inlet end region of the housing, in which case the apparatus further includes first and second adjustable channel spacers at an outlet end region of the housing, operable to resiliently deform the channel members to adjustably inwardly space the channel members from the sides at the outlet end region, to adjustably define the venturi accelerator. Effectively, this permits the intensity of the venturi effect to be adjusted to account for the needs of different locations or different conditions at the same location, or different applications. For example, to compensate for slower water currents, it is generally desirable to bring the converging walls closer together, to increase the intensity of the venturi effect.
In addition, or alternatively, the turbulence producing mechanism may include at least one blocking member disposed in an outlet end region of the housing.
The housing preferably has a floating object deflector. This serves to deflect floating objects away from the housing, without passing through it.
The solid object diverter preferably has a hydrodynamic shape, such as a teardrop shape, for example.
The apparatus may further include a data acquisition unit for acquiring environmental data.
The floats preferably have hydrodynamic shapes. The floats may include first and second outer fins extending outwardly from opposite sides of an inlet end region of the housing, and extending rearwardly toward an outlet end region of the housing, substantially parallel with the sides. Respective fin spacers extend outwardly from the sides and engage with the respective fins to space the fins from the sides. The floats may then include a buoyant medium in a space defined between the fins and the sides of the housing. It has been found that such a float improves the hydrodynamic shape of the apparatus.
At least one of the floats may include a watertight control housing for containing a control unit within the float.
The apparatus preferably includes a tether connector for tethering the apparatus to an object. For example, an inlet end region of the housing may be connected to a tether which in turn is connected to a fixed object at the bottom of the body of liquid, to ensure that the inlet end region of the housing remains upstream from an outlet end region of the housing.
In accordance with another aspect of the invention, there is provided a method of extracting liquid from a body of liquid. The method involves positioning a solid object diverter in the liquid body to admit liquid into a cavity of the solid object diverter while admitting liquid from the cavity into an inlet opening of a conduit terminator about which the solid object diverter extends.
In accordance with another aspect of the invention, there is provided a method of guiding fish, involving disposing a plurality of water turbulence generators in a body of water at a plurality of respective positions along a desired fish path.